Make ClearBrowsingDataHandler only observe its own removal task

chrome/browser/browsing_data/browsing_data_remover.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/browsing_data/browsing_data_remover.h"
 
 #include <map>
 #include <set>
 #include <string>
 
@@ skipping 313 matching lines @@
 }
 
 void BrowsingDataRemover::Shutdown() {
   history_task_tracker_.TryCancelAll();
   template_url_sub_.reset();
 }
 
 void BrowsingDataRemover::SetRemoving(bool is_removing) {
   DCHECK_NE(is_removing_, is_removing);
   is_removing_ = is_removing;
-  FOR_EACH_OBSERVER(Observer, observer_list_,
-                    OnBrowsingDataRemoving(is_removing));
 }
 
 void BrowsingDataRemover::Remove(const TimeRange& time_range,
                                  int remove_mask,
                                  int origin_type_mask) {
   RemoveInternal(time_range, remove_mask, origin_type_mask,
                  std::unique_ptr<RegistrableDomainFilterBuilder>(), nullptr);
 }
 
 void BrowsingDataRemover::RemoveAndReply(
@@ skipping 1135 matching lines @@
   waiting_for_clear_offline_page_data_ = false;
   NotifyIfDone();
 }
 #endif
 
 void BrowsingDataRemover::OnClearedDomainReliabilityMonitor() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   waiting_for_clear_domain_reliability_monitor_ = false;
   NotifyIfDone();
 }